This has been the case for Device-based triggers, conditions, and actions since they were introduced. If you want the entity ID in plain text use Entity-based components.
Everything you see in the UI is serialized as JSON, which does not support comments.
There are multiple threads about this kind of thing ( 1, 2, 3 )
Comments are supported if you just use pure YAML, but the trade off is that you can’t use the UI editors.